In the operation of refuse and other solid waste material hauling carriers, some having a rearwardly moveable pushblade or ejector for compacting or ejecting the load from a rear opening in the carrier, the tailgate can be skewed away from its normally orthogonal relationship with the sidewalls by the force of the compaction of the load against the closure points between the tailgate and the sidewalls. A tailgate which is pivoted about a vertically oriented hinging mechanism between the tailgate and one of the two sidewalls of the carrier resists the compaction forces adequately at the hinge point. However, at the closure between the free end of the tailgate and the other sidewall, the load compaction forces cause a loss of closure integrity. This loss of closure integrity can be seen as the skewing of the closure or the loss of the orthogonal relationship between the tailgate and the sidewall. The term most commonly used to describe this problem is bulging.
Bulging of the tailgate and sidewall adjacent the free end of a vertically hinged tailgate can occur at the top or at the bottom of the tailgate-sidewall closure. It has previously been found that latch plates, one of which is attached to the tailgate and extends outward from the free end of the tailgate and then bends at right angles to mate with the one which is attached to the external lateral surface of the adjacent sidewall, resolve the problem quite efficiently. Use of such a latch plate design requires convenient access to the latch plates by an operator due to the manual engaging and disengaging of the latch plates by the insertion of a keeper to keep the tailgate plate or hasp in place over the sidewall plate or staple.
Assuming that the operator of the refuse carrier is of normal height, only those latch plates which were within reach of the operator standing on the ground could be conveniently engaged or disengaged. Any such latch plates which were placed at or near the upper extent of the carrier tailgate-sidewall closure would not be conveniently reachable by an operator standing on the ground. An operator would be required to climb up the sidewall of the carrier to engage or disengage these latches or a control mechanism operable from the ground would be required. An operator may or may not be able to accomplish the disengaging of these latches if the compaction forces have skewed the closure joint. The keeper may be jammed in place and the operator may not be able to disengage the latch without first relieving the pressure exerted on the tailgate-sidewall closure joint.
There have been attempts at remedying these problems for overhead hinged tailgate assemblies where the operator must release both sides of the lower tailgate, or all the latches at the same time. With an overhead tailgate hinge the skewing of the tailgate-sidewall closure cannot occur because the tailgate is secured to both sidewalls by the hinging mechanism. Further, since most of the latches appear at the bottom of the tailgate, the operator can reach the latches to operate them conveniently.
Another attempt at remedying the problem of compaction pressure skewing the tailgate-sidewall closure joint for outwardly swinging tailgates with vertically oriented hinging mechanisms along one side thereof is the introduction of a control arm for operating each of several latches simultaneously. The control arm causes the insertion of a tongue of each of several latch plates located on the tailgate into an opening in each of several mating latch plates located on and extending rearward of the sidewall locking the tailgate in a closed position. However, the rearward pressure of the waste compaction process jams the tongue against the side of the opening in the sidewall latch plate jamming it in place. Once jammed, the tongue inhibits the free movement of the control arm and the other latches of the mechanism for disengaging the latching mechanism and unlocking the tailgate. Relief from the compaction pressure by forcing the tailgate inward against the rear of the sidewall is required before normal operation of the latch can be resumed. Inherent in the jamming of this type latch mechanism is the loss of joint closure integrity caused by the skewing of the tailgate and the sidewall away from their normal orthogonal relationship.
The problem of loss of integrity in tailgate-sidewall closure occurs in open topped carriers with compaction/ejection assemblies using a sidewall/tailgate hinging mechanism. This type hinging mechanism permits the tailgate to swing out from the load bed about the hinge positioned vertically at the joint between one sidewall and the tailgate. Because of the hinge mechanism the compaction forces do not effect this joint between the tailgate and the sidewall. However, the opposite sidewall closure with the tailgate is entirely different. Only conventional latches had been used which permitted the loss of integrity of the closure, the loss of orthogonality between the sidewall and the tailgate, and the skewing of the joint. This resulted in the inability to open the latches at the tailgate-sidewall closure when the load was compacted against the tailgate requiring partial manual removal of the refuse from the carrier until the pressure was released allowing the latches to be operated.
It is, therefore, an object of the present invention to provide a tailgate-sidewall joint closure for vertically hinged tailgates which will not lose its integrity or orthogonality with the exertion of compaction forces against the joint closure.
It is a further object of the present invention to provide a latching system for preventing the loss of integrity of the tailgate-sidewall joint closure in vertically hinged tailgate systems for solid waste carriers which is engagable or disengagable by the operator from the ground.
It is another object of the present invention to provide a latching system which operates several latches at a time through the use of a single control mechanism.
Other objects will appear hereinafter.